Ionic and Capacitive Artificial Muscle for Biomimetic Soft Robotics

Abstract

We report here the development of an actuator with an ionic electroactive polymer (IEAP) laminate that is exclusively designed to exhibit a combination of high electrically induced strain and high bending modulus. The newly constructed laminate is one of the few IEAPs meeting the requirements for use in miniature soft robotics. The laminate has activated carbon-based electrodes and ionic liquid is used as an electrolyte. Layers of compliant gold foil are used as current collectors. The superior performance of the IEAP laminate is demonstrated by constructing a centimeter-scale robot propelled by a single IEAP actuator. The cyclic locomotion of the robot is inspired by the movements of an inchworm, while the IEAP laminate is used concurrently as an actuator and a structural member. The 830-mg robot is able to crawl on a smooth surface in open air, solely by undulation of its body. The microprocessor-controlled robot has an on-board lithium battery and uses a pulse-width-modulated signal to drive the IEAP actuator. The robot is able to carry its own power supply and even an extra payload. The constructed biomimetic robot is distinctive for the use of a non-planar actuator whose shape is programmed during the manufacturing process.

Inkjet‐printed hybrid conducting polymer-activated carbon aerogel linear actuators driven in an organic electrolyte

“…So-called artificial muscles can be applied as actuators and sensors in medicine [18][19][20], soft robotics [21,22], micromanipulation [22,23] and lab-on-a-chip devices [24]. Electrically conductive polymers are attractive materials for ionic-type actuators because actuation occurs at a low voltage (≤7 V) [25].…”

A power-autonomous self-rolling wheel using ionic and capacitive actuators

“…The CCs need to have a sufficient level of electrical conductivity and to be compliant; the choice of appropriate materials for CCs is very limited. Thin solid gold foils have provided the highest electric conductivity without compromising to the compliance [12]. However, as the thickness of the gold CC is extremely small (<1 μm), the maximum current that can pass through this CC is limited to only approximately 10 mA per 1 mm width; otherwise, the thin CCs would burn out as a result of Joule heating and the IEAP actuator would fail.…”

“…The actuator has carbide-derived carbon electrodes, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate as the electrolyte, and poly(vinylidene fluoride-co-hexafluoropropylene) as the membrane and the binder for the electrode. Its fabrication and electromechanical properties are described in our previous work [12]. Its distinctive properties are listed in Table 1.…”

“…When the driving signals are appropriately commuted, the wheel starts rolling due to torque M ( Figure 1b). <50 Ω cm 2 [12] Electrical capacitance 0.15 F cm -2 [12] Thickness ~450 μm…”

“…Before deployment in the robot, the IEAP actuator laminates are heat-treated to attain arched initial shape; the heattreatment procedure is reported in our previous work [12]. Table 1.…”